The present disclosure relates to a nonaqueous electrolytic solution secondary battery capable of enhancing a discharge capacity retention rate at the time of repetition of charge and discharge.
In recent years, a number of portable electronic appliances such as a camera-integrated VTR, a digital still camera, a mobile phone, a personal digital assistant and a laptop computer, each achieving a reduction in size and weight, have appeared. With respect to batteries, in particular, secondary batteries as a portable power source for such electronic appliances, intensive studies have been conducted for the purpose of enhancing the energy density. Of secondary batteries, lithium ion secondary batteries using carbon for a negative electrode active material, a lithium-transition metal complex oxide for a positive electrode active material and a nonaqueous solvent such as a carbonate mixture for an electrolytic solution have been widely put to practical use because they are able to obtain a high energy density as compared with lead batteries and nickel-cadmium batteries which are a nonaqueous electrolytic solution secondary battery of the related art.
In particular, laminate type batteries using an aluminum laminated film for an exterior are lightweight, and therefore, the energy density is high. In the laminate type batteries, it is carried out to incorporate a polymer as an electrolyte together with an electrolytic solution. In such a laminate type polymer battery, when the electrolytic solution is swollen in the polymer, deformation of the laminate type battery can be suppressed, and in particular, gel electrolyte batteries using a gel polymer obtained by swelling an electrolytic solution in a polymer to gel it are widely used.
However, since the laminate type battery is easy to cause blister in a high-temperature atmosphere because its exterior is soft, it is carried out to incorporate 80% by mass or more of a cyclic carbonate having a high boiling point in an electrolytic solution (see, for example, JP-A-2001-167797).
However, the cyclic carbonate has a high viscosity, and hence, there was involved such a problem that a discharge capacity retention rate at the time of repetition of charge and discharge is reduced.
Thus, it is desirable to provide a nonaqueous electrolytic solution secondary battery which, even when a cyclic carbonate is incorporated in a high concentration in a nonaqueous electrolytic solution, is able to enhance a discharge capacity retention rate at the time of repetition of charge and discharge.